1. Field of the Invention
This disclosure relates generally to the field of mobile telephony, and in particular to setting TTY-modes in a mobile device using user-settable entries in an address book or other applications residing on the mobile device.
2. Description of the Related Art
Teletypewriters (TTYs), also known as telecommunication devices for the deaf (TDDs), enable the deaf or hearing impaired to communicate through the telephone system. A typical TTY device connects to a telephone through a jack, or, an existing telephone line. Historically a tone sequences transmitted by a TTY device representing a text message from a sender are received by a counterpart TTY device at the receiving end. During transmission, the tone sequences are converted to signals represented by zeroes and ones by a transmission protocol such as the 5-bit Baudot Code which maps 5-bit tone sequences to letters, numbers, and punctuation to allow transmission of text messages between the corresponding parties. These communications are not understood (coded or decoded) by non-TTY devices.
TTY text message is displayed on a TTY device in a single line whereby TTY “etiquette” between the two people using TTY devices is required to ascertain which correspondent should be typing next, and which text on the display belongs to who.
Mobile devices, or user equipment (UEs), that allow a TTY device to be connected through a jack require that a user pre-set the UE to be in TTY-mode before making a TTY call. This is typically done through a series of menu selections at a user interface (UI). Once the TTY call is finished, the user must go through one or a series of menus at the UI to de-select TTY-mode.